Panoramic receiver



May 20, 1952 G. P. MCCOUCI-I ET AL PANORAlI/IIC RECEIVER Filed Feb. 18, 1946 Io I2 FIG.I F

' PANORAMIG I SUPERHET. TUBE RCVR.F| I 3A .5

IIIIIEI II A IIII OSCILLATOR MIXER AMPUFIER DETECTOR OUTPUTS OR FILTER N k I6 I7 I I 23:51:: 7 IN FIGS.| AND; MIXER l5 A MAY BE OMITTED IF AMPLIFIER RGVR F2 I6 Is MADE NON-LINEAR Io l2 FIG. 2 PANORAMIG O.R. SUPERHET. TUBE RCVR l TUNED NA lzlg gw 0R i LATofi MI XER UNTUNED I AMPLIFIER ETECTOR OUTPUTS K MIXER 0R lgLTER I4" Is I? LocAL {I OSCILLATOR FIXED FREQUENCY 4 AUXILIARY I I9 I SUPERHET.

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F2 INVENTORS. I GORDON P. Mc COUCH DONALD K.REYNOLDS QJ AZP.

ATTORNEY Patented May 20, 1952 UNIT ED STATES PAT EN'T OFFICE 2,597,358 PANORAMIC mien-IVER Gordon lV IcCo'uch, Boonton, and'bbnald' K: Reynolds; Cambridge, Mass., assignorsto the United: States of America as representedby the' Secretary of War Application February 18, 1946,.Serial No; ems

18 Claims (01; 250 2 l This invention relates to electrical apparatus and more particularly to panoramic receiving systems. I

Panoramic receivers provide' a visual display a furt er object of the" present inventi e to provide an indication on said c'athc ide r'y tube of the frequency to which said auxiliary receiver iS tuned.

on a cathode ray tube of the signals present in a 5 Otherobjects and advantages of the invention band of frequencies. Usually the signals appear will'be apparent during the course 'ofthe'follow its vertical pips on a horizontal base line which ing description. v V v V a w is'laid out infrequency units; 1 The panoramicreceiver' and theaiiiciliaryllis- In a former method ofpanoramic' presentation, ten-through receiver are conventional superhet theso called panoramic adapter" has been used. 19 erodyne receivers; The present invention is'c'on- The panoramic adapter is coupled into a standcerned primarily with various methods of prof ardsuperheterodyne receiver at a point between vidinganjindic'ation on'the cathode ray tube of the m xer Stage ahdthe intermediate frequency the freduncyto which the auxiliary lcivi is amplifier of the standard receiver. The panotuned; V I a I ramic adapter itself includes a broad band am- There are three possible cases depen ing on plifier havinga double hump frequency'res'ponse the" relation between the intermediate frequen characteristic, a panoramic mixer having a frecies and the local oscillator frequencies of the quency modulated local oscillator associated two superhetero'dyne' receivers: r v v H therewith, a narrow band intermediate fre 1. Intermediate frequencies equal; loc'aloscilquencyamplifier, a detector, an amplifier and a 20 lat'o'rs operate onsame side of signal frequency cathode ray tube. One set of deflection plates band. a V I j I H r H A of the cathode ray tube is connected to the out- 2. Intermediate frequenciesjunequal; locales; put of the amplifier and the otherset of defieccillato'rs operate on same side ofsigna'l frequency tion plates is connected to a voltage which i's a band; I Y H r function of the instantaneous frequency of the Intermediate irequencies qual orjun'equal; frequency modulated local oscillator; Hence; a local oscillators operate on opposite' sides of 'sig panoramic presentation of the signals present in mi frequency band. t a, p h h the'mixer-output' of the standardreceiver is dis- Fqra'ch of these threecafs s, several a1 "ma; played on the cathode ray tube. The 1 double tive'methods arehdnside'redfor indicatingfth hump frequency response characteristic of "the frequencysetting of the auxiliaryreceiveron the broadband amplifier of the panoramic adapter is panoramic receiver cathode ray 'tube; I I U intended to compensate forth sloping' sides of In' easel, the local oscillatoif outputs of the the qu en me she'r 1a the wo. te i i' mw eneer, abanda m-5' standard receiver mixer" output. The resultant currence of the null freduency'point between aid shouldbea fairlyuniform frquency'respons 5 outputs may be utilized for'indica'tin characteristic (though limited frequency band) at the output of the broadband amplifier of the panoramic adapten There are several disadvantages in" using the panoramic adapter. Inherently the panoramic presentation is confined :td a fairlylirnited band of frquencies- In addition," tuning the stand-1 ard receiver will alter the'-panorainic display; wliic isfcdr'ifusine'and particularly undesirable we re it is he ssary to keeptr'alcliof a number-of different-signals! v &

An object of the present invention is to provide apanorarnic receiving System includingtwo separatesuperheterodyne receivers; namely a panoramic supr'hete'rodyne receiver adapted to furnish a panoramic presentation on a cathode ray tube of the signals in a band of frequencies and-"a separate auzii-ili'ary listen-through super: h'ete dyn'e receiver which maybe tuned toany trequeacy withm said band of frequencies:

flu c S tti u e aux lia y. r @WfiliiflQWWiWhEh thenii tfeirerl; .7 the'lqcelle q ll tor 0 e efre y ed and he acquies 9M0 t s. j s dl n e null i equ nci q ma be relie i i ic me he frequency" setting: of the auxiliary" re htrddyfied; and the occurenc ofth whi hfis. ihw fi ee e iq emy 12 i intermediate freq which event 'thei'nethodsef case 1 may' be utilize V p case 3' the wearbsen'cwwoutpuw "may be heterodyned and the occurrence of the frequency which is the sum frequency of the intermediate frequencies of the two receivers may be utilized for indicating the frequency setting of the auxiliary receiver. In another less preferable method, a frequency converter having a fixed frequency local oscillator tuned to said sum frequency may be inserted in series with the output from one of said local oscillators, in which event the methods of case 1 may be utilized.

In the accompanying drawing forming a part of this specification, Fig. 1 is a block diagram illustrating the preferred embodiment of the present invention and is applicable to cases 1, 2 and 3 while Fig. 2 is a block diagram illustrating another embodiment of the present invention which is applicable to cases 2 and 3.

In Fig. 1, numeral I designates a panoramic superheterodyne receiver for a band of frequencies. Numeral II designates an auxiliary listenthrough superheterodyne receiver which may be tuned to any frequency within said band of frequencies.

The intermediate frequencies of the panoramic superheterodyne receiver and of the auxiliary superheterodyne receiver are designated as F1, and F2 respectively.

The panoramic superheterodyne receiver ID is equivalent to the ordinary superheterodyne receiver except for its mixer and local oscillator. The panoramic superheterodyne receiver III has a mixer stage with a frequency modulated local oscillator. The output of panoranimc receiver Ii is electrically connected to one set of deflection plates of a cathode ray tube l2. The other set of deflection plates of the cathode ray tube I2 is electrically connected to a voltage which is a function of the instantaneous frequency of the frequency modulated local oscillator.

Numerals I3 and I4 designate electrical connections from the local oscillators of panoramic receiver I0 and auxiliary receiver II respectively to a frequency mixing circuit I5. A narrow band amplifier I6, is electrically connected to the output of frequency mixing circuit I5. The frequency to which amplifier I6 is tuned is designated as F3. A detector I1 is electrically connected to the output of amplifier I6. The output of detector I1 is electrically coupled to cathode ray tube I2.

Fig. 2 is identical with Fig. 1 except that a frequency conversion circuit I8 having a fixed frequency local oscillator I9 is inserted in series with either electrical connection I3 or electrical connection I4. The frequency of oscillator I9 is designated as F4.

Although the frequency conversion circuit I8 and its associated local oscillator I9 are shown in Fig. 2 as inserted in the electrical connection I4'I4" from the local oscillator auxiliary receiver II to mixing circuit I5, it is to be understood that they may be inserted equally well in the connection from the local oscillator of panoramic receiver III to frequency mixing circuit I if desired.

The values of F3 and F4 for each of the three cases mentioned above will now be considered.

(1) For F1=F2 and the local oscillators of both receivers operating on the same side of the signal band of frequencies, there are two possible values for F3 depending upon which method is used:

(a). F3 may be some intermediate frequency, comparatively small with respect to the band of frequencies presented on cathode ray tube I2. In this method a double pip will be obtained on cathode ray tube I2. The two pips will straddle the frequency setting of the auxiliary receiver, each pip being F3 frequency units displaced from said frequency setting. This is the preferred method for case 1.

(b). F; may be approximately zero (i. e. amplifier is may be an audio amplifier). In this method a single pip appears on cathode ray tube I2 at the frequency to which the auxiliary receiver is tuned. This method is the less preferable method for case 1.

(2) For FITLFZ and the local oscillators of both receivers operating on the same side of the signal band, then for the preferred embodiment shown in Fig. 1, F3 is the difference frequency between F1 and F2. For the other embodiment, shown in Fig. 2, F4 is the difference frequency between F1 and F2, while F3 is determined as under case 1.

(3) For F1=F2 or Fl7 F2 and the local oscillators operating on opposite sides of the signal band,.then for the preferred embodiment shown in Fig. 1, F3 is the sum of F1 and F2. For the other embodiment, shown in Fig. 2, F4 is the sum of F1 and F2, while F3 is determined as under case 1.

It is to be understood that the frequency mixing circuit I5 and amplifier I6 may be replaced by various equivalents. Thus amplifier I6 may be replaced by a band pass filter having a similar frequency response characteristic. Inasmuch as the frequency mixing circuit I5 is essentially a non-linear circuit, the frequency mixing circuit I5 and the amplifier I6 could be combined and their function served by a single non-linear narrow band amplifier.

The presentation of the indicator signal may be made in various ways:

1. Pips in the same direction as signal pips on cathode ray tube I2.

2. Pips in opposite direction to signal pips on cathode ray tube I2.

3. Trace brightening of cathode ray tube I 2.

4. Trace darkening of cathode ray tube I2.

Presentations I and 2 may be obtained by applying the output of detector I! (with proper polarity) to the appropriate set of deflection plates of cathode ray tube I2. In presentations 3 and 4, the output of detector H (with proper polarity) is applied to the grid-cathode circuit of cathode ray tube I2.

This panoramic receiving system has several important advantages:

1. A detailed study of any signal or signals selected from the panoramically presented band of frequencies may be made without interruption or without interfering with the panoramic presentation during the listening period.

2. Rapid shifting of the auxiliary receiver to new frequencies or the following of signals shifting in frequency is possible.

3. Accurate alignment of the tuning of the auxiliary receiver with that of the signal under investigation is possible. I

It will be apparent that there may be deviations from the invention as described which still fall fairly within the spirit and scope of the invention.

Accordingly we claim all such deviations which fall fairly within the spirit and scope of the invention as identified in the hereinafter appended claims.

What is claimed is:

1. A panoramic receiving system for a band of frequencies including a panoramic superheterodynereceiver for said band of frequencies, a

cathode ray: tube electrically connected to the output of said panoramic superheterodyne receiver, an auxiliary superheterodyne receiver adaptedv to be tuned over said band of frequencies, the intermediat frequencies of said receivers being unequal and the local oscillators of said receivers operating on the same side of said band of frequencies, a. non-linear circuit electrically connected to-the outputs of said local oscillators and adapted tofurnish the difference frequency between the intermediate frequencies of said receivers, detecting means for rectifying the output of said non-linear circuit and means forelectrically couplingthe output of said detecting means to said cathode ray tube.

2. A. panoramic receiving system as in claim 1 in-which said non-linear circuit includes a frequency mixing circuit and a narrow band amplifier tuned to said difference frequency and electrically connected to the output of said frequency mixing circuit. 1

3. A panoramic receiving system as in claim 1 in which said non-linear circuit includes a frequency mixing circuit and a band pass filter tuned to said difference frequency and electrically connected to the output of said frequency mixing circuit.

4. A panoramic receiving system as in claim 1 in which said non-linear circuit includes a nonlinear narrow band amplifier tuned to said difference frequency.

5. A panoramic receiving system for a band of frequencies including a panoramic superheterodyne receiver for said band of frequencies, a cathode ray tube electrically connected to the output of said panoramic superheterodyne receiver, an auxiliary superheterodyne receiver adapted to be tuned over said band of frequencies, the intermediate frequencies of said receivers being unequal, the local oscillators of said receivers operating on opposite sides of said band of frequencies, a non-linear circuit electrically connected to the outputs of said local oscillators and adapted to furnish the sum frequency of the intermediate frequencies of said receivers, detecting means for rectifying the output of said non-linear circuit and means for electrically coupling the output of said detecting means to said cathode ray tube.

6. A panoramic receiving system as in claim 5 in which said non-linear circuit includes a frequency mixing circuit and a narrow band amplifier tuned to said sum frequency and electrically connected to the output of said frequency mixing circuit.

'7. A panoramic receiving system as in claim 5 in which said non-linear circuit includes a frequency mixing circuit and a band pass filter tuned to said sum frequency and electrically connected to the output of said frequency mixing circuit.

8. A panoramic receiving system as in claim 5 in which said non-linear circuit includes a nonlinear narrow band amplifier tuned to said sum frequency.

9. A panoramic receiving system for a band of frequencies including a panoramic superheterodyne receiver for said band of frequencies, a cathode ray tube electrically connected to the output of said panoramic superheterodyne receiver, an auxilarly superheterodyne receiver adapted to be tuned over said band of frequencies, the intermediate frequencies of said receivers being unequal and the local oscillators of said receivers operating on the same side of said band of fresion circuit and tuned to the difference frequency between the intermediate: frequencies of said 'r'e ceivers, a non-linear circuit electrically connected' to the output of-said frequency conversion circuit and to the output ofthe': other of said localescillators, detectingmeans electrically con-nected to the output of saidnon-line'ar circuit andmeansfor electrically coupling the output of said de tecting means to said cathoderay tube;

10. A panoramic receiving system asinclaim 9' in which said non-linear circuitincludes a fre quency mixing: circuit: and a narrow band 'intel-F mediate frequency amplifier electricallyconnect ed to the output of said frequency mixing circuit.

11. A panoramic receiving system as in claim 9 in which said non-linear circuit includes a nonlinear narrow band intermediate frequency amplifier.

12. A panoramic receiving system for a band of frequencies including a panoramic superheterodyne receiver for said band of frequencies, a cathode ray tube electrically connected to the output of said panoramic superheterodyne receiver, an auxiliary superheterodyne receiver adapted to be tuned over said band of frequencies, the intermediate frequencies of said receivers being unequal, the local oscillators of said receivers operating on opposite sides of said band of frequencies, a frequency conversion circuit electrically connected to the output of the local oscillator of one of said receivers, a fixed frequency oscillator associated with said frequency conversion circuit and tuned to the sum frequency of the intermediate frequencies of said receivers, a non-linear circuit electrically connected to the output of said frequency conversion circuit and to the output of the other of said local oscillators, detecting means electrically connected to the output of said non-linear circuit and means for electrically coupling the output of said detecting means to said cathode ray tube.

13. A panoramic receiving system as in claim 12 in which said nonlinear circuit includes a frequency mixing circuit and a narrow band intermediate frequency amplifier electrically connected to the output of said frequency mixing circuit.

14. A panoramic receiving system for a band of frequencies, including a panoramic superheterodyne receiver for said band of frequencies, a cathode ray tube electrically connected to the output of said panoramic receiver, an auxiliary superheterodyne receiver tunable over the said band of frequencies, the intermediate frequencies of said receivers being unequal, a non-linear circuit means electrically connected to the outputs of the local oscillators of said receivers for deriving a beat frequency signal from the outputs of said oscillators, detecting means for rectifying the output of said non-linear circuit means. and means for electrically coupling the output of said detecting means to said cathode ray tube.

15'. The system defined in claim 14, wherein the said local oscillators operate on the same side of said band of frequencies.

16. The system defined in claim 14, wherein said non-linear circuit means includes a frequency mixing circuit and an amplifier tuned to said beat frequency and electrically connected to the output of said frequency mixing circuit.

memes;

17. flhe system defined in claim 14, wherein thelocal oscillators of said receivers operate on the same side of said band of frequencies and said non-linear circuit means includes a frequency mixing circuit and a band pass filter tuned to the difference frequency between the intermediate frequencies of said receivers.

18. A panoramic receiving system for a band of frequencies, including a panoramic superr heterodyne receiver for said band of frequencies, a cathode ray tube electrically connected to the output of said panoramic receiver. an auxiliary superheterodyne receiver tunable over the said band of, frequencies, the intermediate frequencies of said receivers being unequal, a non-linear circuit means electrically connectedto the outputs of the local oscillators of said receivers for de- 8 riving a beat frequency signal from said outputs having a frequency equal to the difference'between the frequencies of said oscillators, detecting means for rectifying the output of said nonlinear circuit means, and means for electrically coupling the output of said detecting means to said cathode ray tube.

' GORDON P. McCOUCH.

DONALD K. REYNOLDS.

REFERENCES CITED UNITED STATES PATENTS Name Date Wallace Jan. 23, 1945 Number 

